Reentry catheter

Abstract

A reentry catheter having a catheter body having a lumen extending axially through a length of the catheter body, a distal port in communication with the lumen, and a flexible distal tip positioned at a distal end of the catheter body. The distal tip can have a first planar surface and a second planar surface that are angled to form a tapered portion in the distal tip. A thickness of the tapered portion in a first direction can decrease along the length of the tapered portion and can be less than a width of the tapered portion in a second direction at every point along the length of the tapered portion such that the tapered portion of the tip is more flexible when bent in the first direction than in the second direction, the second direction being normal to the first direction.

What is claimed is: 
     
       1. A reentry catheter comprising:
 a catheter body having a first end and a second end; 
 a lumen extending axially through a length of the catheter body; 
 a distal port in communication with the lumen, the distal port being at an acute angle relative to an axial centerline of the catheter body; and 
 a flexible distal tip positioned at a distal end of the catheter body, the distal tip having a first planar surface and a second planar surface that are angled to form a tapered portion in the distal tip, wherein:
 the first and second planar surfaces of the distal tip extend along a length of the tapered portion generally to a distal end of the distal tip such that the tapered portion of the distal tip extends to the distal end of the distal tip; 
 a thickness of the tapered portion in a first direction decreases along the length of the tapered portion and is less than a width of the tapered portion in a second direction at every point along the length of the tapered portion such that the tapered portion of the tip is more flexible when bent in the first direction than in the second direction, the second direction being normal to the first direction; and 
 the port is in communication with the lumen and is configured to direct a guidewire that is advanced through the lumen out of the port in a lateral direction, the lateral direction being in a plane that is coincident with the first direction of the tapered portion and intersects the axial centerline of the catheter body. 
 
 
     
     
       2. The reentry catheter of  claim 1 , wherein the distal end of the tapered portion is at least approximately two times as flexible in the first direction as compared to the second direction. 
     
     
       3. The reentry catheter of  claim 1 , wherein the distal end of the tapered portion is from approximately three times to approximately five times as flexible in the first direction as compared to the second direction. 
     
     
       4. The reentry catheter of  claim 1 , wherein the distal tip has an asymmetric shape such that the distal tip is more flexible in the first direction than in a third direction, wherein the third direction is opposite to the first direction. 
     
     
       5. The reentry catheter of  claim 1 , wherein the distal end portion of the distal tip is offset from a centerline of the distal tip by a distance that is from approximately 10% to approximately 50% of the diameter of the catheter body. 
     
     
       6. The reentry catheter of  claim 1 , wherein, at any point along the tapered portion of the distal tip, a second moment of area of the distal tip in the second direction is greater than a second moment of area of the distal tip in the first direction. 
     
     
       7. The reentry catheter of  claim 1 , wherein a second moment of area of the distal tip in the second direction is greater than a second moment of area of the distal tip in the first direction at all points along a length of the tapered portion and wherein a difference between the second moment of area of the distal tip in the second direction and the second moment of area of the distal tip in the first direction increases along the length of the tapered portion. 
     
     
       8. The reentry catheter of  claim 1 , further comprising a radiopaque marker adjacent to the distal port. 
     
     
       9. The reentry catheter of  claim 1 , further comprising a core member positioned in the tapered portion configured to increase a bending stiffness of the distal tip in the second direction more than in the first direction. 
     
     
       10. The reentry catheter of  claim 1 , wherein the port is configured to direct a guidewire that is advanced through the lumen out of the port at an angle of from approximately 35 degrees to approximately 90 degrees relative to the axial centerline of the catheter body. 
     
     
       11. The reentry catheter of  claim 1 , wherein the width of the tapered portion of the distal tip continually decreases along the length of the tapered portion. 
     
     
       12. The reentry catheter of  claim 1 , wherein the catheter body comprises one or more of single wire braiding, multi-wire braiding, coils, and any other suitable metal support structures. 
     
     
       13. A reentry catheter comprising:
 a catheter body having a first end and a second end; 
 a lumen extending axially through a length of the catheter body; 
 a distal port in communication with the lumen, the distal port extending generally in a first direction away from an axial centerline of the catheter body; and 
 a flexible distal tip positioned at a distal end of the catheter body, a distal end portion of the distal tip having:
 a first stiffness when a distal end portion of the distal tip is bent in the first direction; and 
 a second stiffness when the distal end portion of the distal tip is bent in a second direction that is normal to the first direction; 
 wherein: 
 the second stiffness of the distal tip when the distal tip is bent in the second direction is greater than the first stiffness of the distal tip when the distal tip is bent in the first direction at every point along a length of the distal tip; and 
 the first stiffness of the distal tip when the distal end portion of the distal tip is bent in the first direction decreases along the length of the distal tip such that the first stiffness is lowest at the distal end of the distal tip. 
 
 
     
     
       14. The reentry catheter of  claim 13 , wherein the second stiffness of the distal end portion of the distal tip when the distal end portion of the distal tip is bent in the second direction is at least approximately twice as high as the first stiffness of the distal end portion of the distal tip when the distal end portion of the distal tip is bent in the first direction. 
     
     
       15. The reentry catheter of  claim 13 , wherein the second stiffness of the distal end portion of the distal tip when the distal end portion of the distal tip is bent in the second direction is at least approximately three times as high as the first stiffness of the distal end portion of the distal tip when the distal end portion of the distal tip is bent in the first direction. 
     
     
       16. The reentry catheter of  claim 13 , wherein a width of the distal tip is approximately the same as or less than a width of the catheter body. 
     
     
       17. The reentry catheter of  claim 13 , wherein the port is configured to direct a guidewire that is advanced through the port to an angle that is from approximately 35 degrees to approximately 90 degrees relative to the axial centerline of the catheter body. 
     
     
       18. The reentry catheter of  claim 13 , further comprising a radiopaque marker adjacent to the distal port. 
     
     
       19. The reentry catheter of  claim 13 , further comprising a core member positioned in the distal tip configured to increase a bending stiffness of the distal tip in the second direction more than in the first direction. 
     
     
       20. The reentry catheter of  claim 13 , wherein the catheter body comprises one or more of single wire braiding, multi-wire braiding, coils, and any other suitable metal support structures. 
     
     
       21. The reentry catheter of  claim 13 , further comprising a means for identifying an orientation of the distal tip in fluoroscopy. 
     
     
       22. The reentry catheter of  claim 13 , further comprising a means for reducing the first stiffness of the distal tip in the first direction. 
     
     
       23. The reentry catheter of  claim 13 , further comprising a means for deflecting a guidewire through the distal port.